Bladed body



L. B. WALES BLADED' BODY Get. 26, 1937.

Filed Nov. 7, 1935 Inventor: Lawrence B.\/\ a|es.

I Jo y (3A9 -||is Attovngy.

Patented Oct. 26, 1937 UNITED STATES PATENT OFFICE BLADED BODY New York Application November 7, 1935, Serial No. 48,675

8 Claims.

The present invention relates to bladed bodies, that is, to methods of and arrangements for manufacturing such bodies or structures, for instance, diaphragms used in elastic fluid turbines for prop erly directing a stream or streams of elastic fluid towards rotary bucket wheels. These diaphragms usually include an inner ring or disk with a plurality of blades or partitions secured to the outer surface thereof and an outer ring or band secured to the outer ends of the partitions. The inner and outer ring together with the partitions define a plurality of nozzles or passages. In such arrangement the blade exit edges are radially or nearly radially directed from a common center. The securing of the partitions or blades to an inner and an outer ring or like members may be accomplished by casting the ends of a plurality of partitions into such rings. In preparation for the actual casting process the blades must be located accurately in the mold and the spaces between the blades, which are to become nozzle passages, protected against the entry of molten metal. This is commonly done by filling these spaces tightly with sand. To produce such a 25 structure of sand and blades, commonly called a core, of the required accuracy, 9. fixture is necessary, often known as a core box, for locating and holding the blades in their correct rela- 9 tive positions while the spaces between blades are being filled with sand.

The object of my invention is to provide an improved method of and an arrangement for producing bladed bodies, such as turbine diaphragms, in which a plurality of spaced partitions, blades or like members have their ends cast into adjacent portions of rings or like holding members. This is accomplished in accordance with my invention by locating and holding the blades, during the formation of the core, with two bands or strips of material having punched openings for receiving end portions of such partitions, blades or like members. The strips or bands for holding the blades in properly spaced relation are made in accordance with my invention from an organic material, such as cardboard, which chars, burns, decomposes or becomes brittle under the influence of heat. The bands or strips with the blades assembled therewith are placed in a core box. As the strips are flexible, spacing blocks are inserted 30 between the strips and the core box walls between the ends of adjacent blades projecting through the strips. Sand is then filled and pounded into the spaces defined between the strips and adjacent blades to form a core. The core together with the strips and blades thereafter is use of strips of material for assembling the blades removed from the core box and put into an oven for drying at a temperature of several hundred degrees F. Under the influence of the heat the strips become brittle or decompose and thus may be removed easily from the dried core. The core then is put into a mold for casting inner and outer holding members to the end portions of the blades. The important feature of this method and arrangement, as will be readily seen, is the and making a core. As stated before, the strips must be made of a certain kind of material which is destroyed or rendered easily destructible after having been exposed to heat. The material best suited to this purpose must have a number of other properties. It must be of such a nature that the core sand does not adhere or bake onto it while in the core oven. In addition to certain cardboards, I have found suitable for the present purpose sheets made of a phenolic condensation product united by an artificial resin and provided with a paper surface molded on one side in such a way that the binder, that is, the artificial resin for the phenolic condensation product does not penetrate the paper completely. This paper side is placed next to the sand. In the core oven the paper chars just sufilcient to make a clean, smooth parting between the sand and the remaining part of the strip so that no trimming of the core is required. Furthermore, the strips should be of a material little or not at all affected by humidity.

For a full understanding of my improved meth- 0d and arrangement of producing bladed bodies, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

In the drawing, Fig. 1 illustrates an elastic fluid turbine diaphragm produced in acordance with my invention; Fig. 2 shows a core box embodying my invention; Fig. 3 is a sectional View through Fig. 2; Fig. 4 shows the arrangement of Fig. 3 upside down with certain parts removed; Fig. 5 shows a core produced in the core box; and Fig.

6 shows the core after completion of the baking process.

The diaphragm shown in Fig. 1 comprises a disk or inner holding member l0 with a rim H. An outer ring or holding member 82 is concentrically spaced from the outer surface of the rim H and a plurality of radially directed blades or partitions l3 uniformly spaced have end portions cast into the rim II and the ring l2 respectively.

The casting of a diaphragm includes the step of producing a core box for making a core, which .32 (Fig. 4) are necessary to form a core.

. During assembly latter is put into a mold in which the diaphragm is cast. A core box according to my invention is shown in Fig; 2. In the present instance, where the diaphragm is of considerable diameter, the core box serves to produce a part or segment of the complete core. The different core segments in known manner are placed together in a mold. The term core will be used hereinafter to designate a segment produced in the core box, The core box includes a box-like frame having concentrically spaced front and rear walls I4 and I5 respectively and radially directed side Walls I6 and II respectively, resting on a base I8. The front and rear walls I4 and I5 each include a removable, tapered wall portion IS and I9a respectively contacting the tapered surface of a stationary portion of the walls I4 and I5 respectively. These stationaryportions are securely fastened to the end walls I6 and I! to form a box-like structure. A supporting ring 20 with a plurality of spaced stops- 2|. rests on the base I8 and has an outer surface engaging the adjacent surface of the wedge-shaped removable wall member I9. The supportingring serves to locate radially the outer end portions of a plurality of blades IS. A similar ring, not visible, is provided for locating the inner end portions of the blades I3. The dimensions of parts I9 and 20 depend upon the dimension of the diaphragm to be produced. The box may be used for the manufacture of different kinds of diaphrag-ms. The blades l3 are supported by two spaced-apart strips 22 and 23 made of a material destroyed or rendered easily destructible under the influence of heat, as pointed out before. A plurality of openings 24are punched intothe strips for receiving and maintaining in properly spaced relation the end portions of the blades I3. The outer and inneredges of the blades engage the stops 2|; In order to prevent deformation of the strips 22, 23 during the core forming, spacing.

blocks 25 are provided between the ends of adjacent blades. Accuracy of the-spacing blocks 25 is necessary only with respect to their thickness in order to insure'uniform and concentric relation between the adjacentsurfaces of the strips 22, 23, and the removable wall sections I9. Otherwise, no accurate machining-ofthe blocks is necessary, it being sufiicient if theyengage-adjacent surfaces of blade end portions along a few points or lines. With this arrangement it;is no longer necessary to accurately machine the sides of the spacing blocks to conform with the curvature of the adjacent sides of the blades. This fact reduces considerably the manufacturing cost of nozzle core boxes made in accordance with my invention. a

Two core print forming blocks 26 and 21 are placed on top of the spacing blocks 25. The blocks 26, 21 have outer surfaces 28 which are inclinedand incontact with correspondingly inclined'surfaces of the walls I4 and I5 respectively. The inner sides 29 of 'the blocks 26, 21

are shaped in accordance with the desiredcore print shape. The arrangement also includes'end blocks 38 and 3| (Fig. 3). All of the aforementioned elements I4 to 3I, together with a plate It is to be noted that these elements also include the blades I3 forming part of the finished product,

in the present instance a turbine nozzle diap r gm; g

of the core box shown in Fig. 2 the strips 22, 23 with the blades I3 are assembled outside the core box. Thereafter one of the removable wall sections I9, one of the supporting rings 28 and the end block 30 are placed into the outer frame or box proper. The assembly of blades IS and strips 22, 23 are placed into the box With the outer ends of the blades bearing against the stops 2I. Thereafter the inner blade-supporting member 20, not visible in the drawing, is placed into the box together with the inner removable wall portion I90. and the end block 31'. Finally, spacer blocks 25 are inserted between adjacent blades, the end block 3| is inserted between the end blade [3 and the sidewall l6, and core print forming blocks 26, 27 are placed on top of the blocks 25. The spaces defined between the strips 22, 23 and between adjacentblades and also between the core print forming blocks 26, 27 are then filled with sand. The sand in known manner is rammed down into these spaces, as shown in Fig. 3. The plate 32 then is placed on top of the box and the box turned over, as shown in Fig. 4, to receive sand from the opposite side of the nozzle passages. After the sand has been pounded into the box, the core together with the strips 22, 23 and the blades it are removed from the box, (Fig. 5). The core is placed in an oven and subjected to heat for a certain period of time, during which the core dries and the strips 22, 23 become brittle, that is, easily removable. A baked core is shown in Fig- 6. I This coreis assembled in known manner with other cores in a mold, that is, plurality of segments are placed end to end to form a complete ring or half of a ring. Metal is cast into the mold to unite with the blade end portions projecting from the core. The uniting of the metal with these end portions is facilitated by the provision of openings 33 in the blade end portions.

Having described the method according to my invention, together with the apparatus for carryingout the method, I wish to have it understood that changes may be made in both the apparatus and the method without departing from the spirit of my invention and the scope of the appended claims. a V l What I claim as new and desire to secure by Letters Patent of the United States, is:

v 1. In the method of forming a core for producing bladed bodies having a plurality of spaced blades cast to holding members, said method comprising assembling the blades and a thin, punched strip having a plurality of spaced openings conforming to the cross section of the blades to receive end portions thereof, filling the spaces intermediate the blades with sand, baking the core, and thereafter removing the strip.

2. In the method of forming a core for producing bladed bodies having a plurality of spaced blades cast to holding members, said method comprising assembling the blades and a strip having a plurality of spaced openings with the end portions of the blades projecting through the openings, said strip being made of a material rendered brittle by the application of heat, filling the spaces intermediate the blades with sand, baking the core, and thereafter removing the strip.

3. In the method of forming a core for producing bladed bodies having a plurality of spaced blades cast to holding members, said method comprising assembling the blades and a strip uct united by an artificial resin filling the spaces intermediate the blades with' sand, baking the core and thereafter removing the strip.

4. In the method of forming a core for producing bladed bodies havinga plurality of spaced blades cast to holding members, said method comprising assembling the blades with a strip having a plurality of spaced openings, said strip being made from a phenolic condensation product united by an artificial resin and a sheet of paper secured to one side of the strip in such a manner that the artificial resin does not penetrate the paper completely.

5. In the method of forming a core for producing bladed bodies having a plurality of spaced blades cast to holding members, the steps of producing a strip from a material which is rendered destructible by the application of heat, forming a plurality of spaced openings in the strip for receiving and holding in position the end portions of a number of blades, assembling the strip with the blades, placing the assembled strip and blades into a core box, forming a core and destroying the strip by the application of heat.

6. In the method of forming a core for producing bladed bodies having a plurality of spaced blades cast to holding members, the steps of forming two strips having a plurality of spaced openings and made from a material which decomposes by the action of heat, inserting the end portions of a plurality of blades into opposite openings of the strips, reinforcing the strips by the insertion of spacing blocks between the projecting end portions of adjacent blades, filling the passages defined by the strips and the blades with core sand to form a. core, subjecting the core with the strips to heat and removing the strips.

7. An article of manufacture for use in the production of bladed bodies having a plurality of spaced blades cast into holding members, such article including a punched strip having a plurality of openings conforming to the shape of the blades and spaced in accordance with the spacing of the blades of the bladed body, said strip being made from a material which changes its properties when subjected to a temperature of a few hundred degrees in such manner as to become easily destructible whereby the strip may be readily removed after the baking of a core including such article.

8. An article of manufacture for use in the production of bladed bodies having a plurality of spaced blades cast into holding members, said article comprising a punched strip with a plurality of spaced openings conforming to the shape of the blades and made from a phenolic condensation product united by an artificial resin and a sheet of paper secured to one side of the strip in such a Way that the resin does not penetrate the paper completely.

LAWRENCE B. WALES. 

